 The Pirates of the Bay: The Frigatebirds
By Biol. Oscar S. Aranda Mena*
Pirates are not only found in the Caribbean; in nature there have always been pirates, who often go unnoticed in front of your very eyes. This is the case of fearful pirates, better known as the Magnificent Frigatebird you see graciously soaring up high patrolling its territory. A common bird in the Banderas Bay, the frigate bird specializes in intimidating other birds and stealing their prey, which might take more effort to fish for themselves. They are birds with great acrobatic qualities and unequaled habits of prey, which are however necessary in the ecosystem, and leave us much to learn about the complex interactions in nature between predator and prey.
A Wingspan of Two Meters … and a Weight of 1.5 kilos!
The frigatebird (Fregata magnificens) is estimated to be the bird with the longest wingspan relative to its body. These silent animals have a body of the size of a chicken, a wingspan of up to 2.3 meters yet only a meter long from its beak to its tail. Because they are essentially air birds, frigatebirds have lost the ability to swim. To lose weight, they have developed hollow bones and have very little oil on their feathers, and are not therefore waterproof, so they will drown if they fall into the water. With less than 1.5 kilograms of weight, they are able to fly for up to a week without rest, and are known to travel distances of up to eight thousand kilometers, and can cross oceans to join other populations.
Acrobatic Food Thieves
 Frigatebirds have developed remarkable flight agility and their aerodynamic design enables them to make extremely rapid movements and spins that challenging the laws of physics. With flexible necks and hooked beaks, they are excellent at catching fish and small sea turtles at the surface.
Their infamous habit of attacking, and intimidating other birds and stealing their meals gave rise to its name, which refers to war ships of the same name. With flight speeds of up to 35 kilometers per hour, frigate birds mercilessly scavenge and harass birds, marine swallows, pelicans and gulls, in flight, biting their feathers aggressively until forced to vomit its food, which they immediately catch and eat in mid-air.
Pirates and Dedicated Parents
Males and females have different colorings. Females have a white chest, while that of males is totally black, with a scarlet red throat pouch devoid of feather called a gular sac. This pouch is inflated like a balloon during mating season to attract females, following a developed ritual. They nest build together, in the canopy of trees or high places, using twigs that are generally stolen from other nests.
Generally a single egg is laid. The chick is born after 50 days and both parents feed in shifts during the first three months. Subsequently only the female will continue caring for the chick for another eight months. Because it takes a long time to raise a chick, frigatebirds only reproduces every two years, and it is common to see a youth as big as its parents waiting patiently to be fed.
During upbringing, the adults may roam up to 150 kilometers daily, in search of food for their chick. Once on their own, juveniles require another seven years until they reach maturity, and can live up to 40 years; a long life for a bird.
Much like pelicans, Frigate birds are able to devour or swallow very large prey, compared to the size of their beak, and it is surprising to watch them catch a fish twice the size of its head. The adult birds have virtually no predators, and have survived thanks to their unethical lifestyle. These pirates of the seas have earned the respect of other birds and anyone fortunate to observe them performing their incredible air acrobatics.
In the Banderas Bay, the Frigate birds can be observed nesting on Los Arcos and on the Marietas Islands, kindly sharing their space with pelicans and other birds. But don’t be fooled, because while Frigate birds may be good neighbors on the ground, watch out for them in the skies as they mercilessly chase other birds through the air, seeking to steal their precious food.
* Oscar Aranda is a biologist dedicated to the conservation of natural resources by means of the environmental awareness and is responsible for a program for the protection of sea turtles in Puerto Vallarta. If you would like more information, visit the following webpage: www.vallartanature.org |
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